User Documentation

72555600000/02/05-2018
Notes on conguration
3.1 Low demand mode of
operation
The safety relay is used with a low demand rate
(low demand mode) when the demand rate of the
relay does not exceed 5x per year and when it does
not exceed double the frequency of the repeat test
(proof test).
The associated technical parameter is the value
PFD
avg
that applies to the duration of the test interval
T
proof
.
3.2 High demand mode of
operation
If the low demand rate mode is not applicable, the
safety relay is to be used as a safety-relevant sub-
system with a high or continuous demand rate (high
demand mode or continuous mode).
The associated technical parameter is the value
PFH that applies to the duration of the test interval
T
proof
.
3.3 Types of malfunctions
A safe failure is not able to render a technical safety
system dangerous or non-functional. The safety re-
lay passes to a predened safe state.
A dangerous, undetected failure has the potential to
render a technical safety system dangerous or non-
functional. The safety relay does not pass to a pre-
dened safe state.
3.4 Test interval
The test interval is the period of time in which tests
are conducted in full and are repeated.
Errors are detected within the framework of the
proof test.
3 Notes on conguration